/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.tsfile.file.header;

import org.apache.iotdb.tsfile.common.conf.TSFileConfig;
import org.apache.iotdb.tsfile.file.MetaMarker;
import org.apache.iotdb.tsfile.read.reader.TsFileInput;
import org.apache.iotdb.tsfile.utils.ReadWriteForEncodingUtils;
import org.apache.iotdb.tsfile.utils.ReadWriteIOUtils;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class ChunkGroupHeader {

    private static final byte MARKER = MetaMarker.CHUNK_GROUP_HEADER;

    private final String deviceID;

    // this field does not need to be serialized.
    private int serializedSize;

    /**
     * constructor of CHUNK_GROUP_HEADER.
     *
     * @param deviceID device ID
     */
    public ChunkGroupHeader(String deviceID) {
        this.deviceID = deviceID;
        this.serializedSize = getSerializedSize(deviceID);
    }

    private int getSerializedSize(String deviceID) {
        int length = deviceID.getBytes(TSFileConfig.STRING_CHARSET).length;
        return Byte.BYTES + ReadWriteForEncodingUtils.varIntSize(length) + length;
    }

    /**
     * deserialize from inputStream.
     *
     * @param markerRead Whether the marker of the CHUNK_GROUP_HEADER is read ahead.
     */
    public static ChunkGroupHeader deserializeFrom(InputStream inputStream, boolean markerRead)
            throws IOException {
        if (!markerRead) {
            byte marker = (byte) inputStream.read();
            if (marker != MARKER) {
                MetaMarker.handleUnexpectedMarker(marker);
            }
        }

        String deviceID = ReadWriteIOUtils.readVarIntString(inputStream);
        return new ChunkGroupHeader(deviceID);
    }

    /**
     * deserialize from TsFileInput.
     *
     * @param markerRead Whether the marker of the CHUNK_GROUP_HEADER is read ahead.
     */
    public static ChunkGroupHeader deserializeFrom(TsFileInput input, long offset, boolean markerRead)
            throws IOException {
        long offsetVar = offset;
        if (!markerRead) {
            offsetVar++;
        }
        String deviceID = input.readVarIntString(offsetVar);
        return new ChunkGroupHeader(deviceID);
    }

    public int getSerializedSize() {
        return serializedSize;
    }

    public String getDeviceID() {
        return deviceID;
    }

    /**
     * serialize to outputStream.
     *
     * @param outputStream output stream
     * @return length
     * @throws IOException IOException
     */
    public int serializeTo(OutputStream outputStream) throws IOException {
        int length = 0;
        length += ReadWriteIOUtils.write(MARKER, outputStream);
        length += ReadWriteIOUtils.writeVar(deviceID, outputStream);
        return length;
    }

    @Override
    public String toString() {
        return "ChunkGroupHeader{"
                + "deviceID='"
                + deviceID
                + '\''
                + ", serializedSize="
                + serializedSize
                + '}';
    }
}
